Vehicle mounted inspection systems and methods

ABSTRACT

Vehicles for use in radiation scanning systems to inspect objects are disclosed. In one embodiment, a vehicle has a supporting portion and a radiation source is movably supported by the supporting portion. The source may be moved along the supporting portion to scan an object. The supporting portion may comprise an expandable portion. The vehicle may comprise a truck and an expandable trailer releasably coupled to the truck. The trailer may comprise telescoping rails. In another embodiment, a vehicle with a supporting portion, which may be an expandable portion, movably supports a detector. Vehicles of the first and second embodiments may be driven to an inspection site, where they may be rapidly deployed on opposite sides of an object to be scanned.

RELATED APPLICATION

The present application is a continuation of U.S. application Ser. No.10/455,864, which was filed on Jun. 6, 2003, now U.S. Pat. No. 6,937,692is assigned to the assignee of the present invention and is incorporatedby reference herein.

FIELD OF THE INVENTION

Radiation scanning systems and, more particularly, vehicle mountedradiation scanning systems.

BACKGROUND OF THE INVENTION

Radiation is commonly used in the non-invasive inspection of objectssuch as luggage, bags, briefcases, and the like to identify hiddencontraband and smuggled goods. Contraband includes guns, knives,explosive devices, as well as illegal drugs, for example. Smuggled goodsmay be identified by comparing the detected contents of objects with amanifest listing of the contents of the objects. As criminals andterrorists have become more creative in the way they conceal contraband,the need for more effective non-invasive inspection techniques hasgrown. While the smuggling of contraband onto planes in carry-on bagsand in luggage has been a well-known, on-going concern, a lesspublicized but also serious threat is the smuggling of contraband acrossborders and by boat in large cargo containers. Only 2%–10% of the 17million cargo containers brought to the United States by boat areinspected. “Checkpoint Terror”, U.S. News and World Report, Feb. 11,2002, p. 52.

One common inspection system is a line scanner, where an object to beinspected, such as luggage, is passed between a stationary source ofradiation, such as X-ray radiation, and a stationary detector. Theradiation is collimated into a vertical fan beam or a pencil beam andthe object is moved horizontally through the beam. The radiationtransmitted through the object is attenuated to varying degrees by thecontents of the object. The attenuation of the radiation is a functionof the density of the materials through which the radiation beam passes.The attenuated radiation is detected and radiographic images of thecontents of the objects are generated for inspection. The radiographicimage reveals the shape, size, and varying densities of the contents.

Standard cargo containers are typically 20–50 feet long (6.1–15.2meters), 8 feet high (2.4 meters) and 6–9 feet wide (1.8–2.7 meters).Air cargo containers, which are used to contain a plurality of pieces ofluggage or other cargo to be stored in the body of an airplane, mayrange in size (length, height, width) from about 35×21×21 inches(0.89×0.53×0.53 meters) up to about 240×118×96 inches (6.1×3.0×2.4meters). Sea cargo containers are typically about 40–50 feet long, 8feet wide and 8 feet high. (12.2–15.2×2.4×2.4 meters). Large collectionsof objects, such as many pieces of luggage, may also be supported on apallet. Pallets, which may have supporting side walls, may be ofcomparable sizes as cargo containers. The term “cargo conveyance” isused herein to encompass cargo containers (including sea cargocontainers) and pallets.

Fixed inspection systems have been proposed for inspecting largecontainers. For example, U.S. Pat. No. 4,430,568 to Yoshida discloses anX-ray system for the inspection of packages, including large shippingcontainers. A conveyor moves the package or container horizontallybetween the X-ray source supported on a floor and a detector array.Similarly, U.S. Pat. No. 4,599,740 to Cable discloses a fixed inspectionsystem, where an X-ray source transmits a continuous beam of radiationacross a conveyor along which the containers to be inspected are moved.The container may be moved either continuously or incrementally. Theradiation transmitted through a container is detected by a “folded”sensor screen or device having two, perpendicular arms, one extendingvertically along a side of the container and the other extendinghorizontally over the top of a container during inspection. The foldedsensor enables the system to have a smaller height than would otherwisebe necessary in order to detect radiation transmitted through the entirecontainer.

It has also been proposed to scan large containers with portable X-rayimaging systems. For example, U.S. Pat. No. 5,638,420 to Armisteaddiscloses a straddle inspection system, wherein a source and a detectorof a radiation scanning system are fixed to a movable frame and theframe is moved horizontally along the length of the container whileimage data is sequentially recorded. U.S. Pat. No. 5,692,028 to Geus etal. discloses an X-ray source mounted on a mobile vehicle and a detectorsupported by a portal shaped assembly extending from the vehicle. Duringinspection of an object, which can be another vehicle, the mobilevehicle is driven past the object, such that the object passes throughthe portal shaped assembly.

U.S. Pat. No. 6,292,533 B1 to Swift, et al. discloses a mobile X-rayinspection system for large objects, such as a cargo container carriedby a vehicle, that uses an X-ray source of 450 kV. The source issupported on a truck and a pencil beam is generated to vertically scanthe vehicle. Detectors, also supported on the truck or a boom extendingfrom the truck, are provided to detect radiation transmitted through andscattered by the contents of the object. In use, a vehicle to beinspected parks alongside the scanning unit on the truck. The source anddetectors are moved horizontally by a translation system within thetruck to horizontally scan the vehicle. Scanning is said to be“exceedingly slow” (⅓–⅙ of a mile per hour).

U.S. Pat. No. 5,917,880 to Bjorkholm discloses an X-ray inspectionapparatus that may be used to inspect cargo containers, that uses X-rayradiation of about 8 MeV, collimated into a vertical fan beam to scan atruck carrying the cargo. A first detector array is aligned with the fanbeam to detect radiation transmitted through the truck. A seconddetector array is provided to detect radiation forward scattered throughthe truck. The truck is moved through the vertical fan beam. Data fromboth detectors is used to determine the average atomic number of theattenuating material in the truck to identify the material content inthe truck. Images indicative of the material content are then prepared.Data provided by the first detector array is also used to formradiographs of the truck.

Such systems tend to be expensive, heavy, complex and difficult totransport and set up. Inspection may be slow. Some systems requireseveral days to assemble and disassemble. Other systems are so longand/or heavy, that they require a special road permit to be driven onhighways.

Improved radiation inspection systems for vehicles, for cargoconveyances carried by vehicles and for other objects are needed.

SUMMARY OF THE INVENTION

In accordance with an embodiment of the invention, a vehicle isdisclosed comprising a supporting portion and a radiation source movablysupported by the supporting portion. The supporting portion may comprisean expandable portion. The expandable portion may be expanded in adirection along a longitudinal axis of the vehicle, for example. Theexpandable portion may comprise at least one rail to movably support thesource. A pair of rails may be provided, for example. The expandableportion may have a first position supported above ground and a second,lowered position, on the ground. The expandable portion may betelescoping. The source may be moved along the expandable portion by amotor, for example.

In accordance with another embodiment of the invention, a vehicle with asupporting portion is disclosed comprising a detector to detectradiation movably supported by the supporting portion. As above, thesupporting portion may comprise an expandable portion. The detector maybe adapted to detect the vertically diverging beam after interactionwith an object being inspected, for example.

In accordance with another embodiment, a vehicle for use in a radiationscanning system is disclosed comprising a supporting portion and a basemovably supported on the supporting portion. A radiation source isrotatably coupled to the base to selectively illuminate objects indifferent locations. For example, the source may be pivotally coupled tothe base. The supporting portion may comprise an expandable portion.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a perspective view of a radiation scanning system inaccordance with one embodiment of the invention;

FIG. 2 a is a side view of a trailer, which may be part of the firstvehicle of the system of FIG. 1, separated from the forward, truckportion of the vehicle;

FIG. 2 b is a side view of a trailer that is similar to the trailer ofFIG. 2 b, having an additional telescoping section;

FIG. 3 is a cross-sectional view of one of the rails of the telescopingsection of the trailer of FIG. 2 a, through line 3—3 of FIG. 2 a;

FIG. 4 is a perspective view of the second vehicle, including theforward, truck portion coupled to a trailer, in a non-deployed position;

FIG. 5 is a side view of the trailer of the second vehicle, with therails in a non-deployed position;

FIG. 6 is a side view of the trailer in a deployed position, with therails lowered to the ground;

FIG. 7 is a front view of the source and the detector of the radiationscanning system of an embodiment of the invention, during scanning of anobject, such as a cargo conveyance on a third vehicle;

FIG. 8 is a side view of the source positioned on a wedge to rotate thedirection of an emitted radiation beam upward;

FIGS. 9–12 are top, schematic views of a radiation scanning system inaccordance with an embodiment of the invention, during various steps ina method of inspecting an object such as a cargo conveyance, inaccordance with an embodiment of the invention;

FIG. 13 is a top, schematic view of the system of FIG. 1, including atrailer portion of an additional vehicle supporting an additionaldetector for increased throughput, during use in inspecting anotherobject;

FIG. 14 is a side view of a source pivotally connected to a base for usewith the system of FIG. 13;

FIG. 15 is a top schematic view of another high throughput system;

FIGS. 16 and 17 are side and front views, respectively, of analternative source for use in the system of FIG. 15, that emits tworadiation beams simultaneously in opposite directions; and

FIG. 18 is a front view of the system of FIG. 15 and the source of FIGS.16 and 17, in use inspecting two objects.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a perspective view of a radiation scanning system 10 inaccordance with one embodiment of the invention. The system 10 comprisesa first vehicle 12 supporting a source 14 and a second vehicle 16supporting a detector 18. A cargo conveyance 20 to be inspected is shownin a gap G between the first and second vehicles 12, 16, in this examplecarried by a third vehicle 22. Preferably, the source 14 and thedetector 18 are movable across the first and second vehicles 12, 16,respectively, to scan the cargo conveyance 20.

Each vehicle 12, 16 comprises respective forward, truck portions 24, 26,rear, carriage portions 28, 30 supporting rear wheels 32, 34, andcentral portions 36, 38 coupling the forward and rear portions. Thesource 14 and the detector 18 are movable across the central portions36, 38, respectively. In this example, the source 14 is adapted to emita vertically diverging beam, such as a vertical fan beam. The detector18 in this example extends vertically to detect the vertically divergingradiation beam after interaction with the cargo conveyance 20.

Also in this example, the central portions 36, 38 comprise respectivepairs of rails 40, 42. The rail pair 40 of the first trailer 12 supportsthe radiation source 14 and the rail pair 42 of the second trailer 16supports the detector 18. Alternatively, either or both of the centralportions 36, 38 may be a single rail. The central portions 36, 38 mayalso comprise other supporting structures besides rails. Either or bothof the central portions 36, 38 may be platforms, for example.

The forward truck portions 24, 26 may be conventional semi-tractortrucks for hauling trailers, for example, such as a Model 379 or othermodels available from Peterbilt Motors Company, A Division of PACCAR,Inc., Denton, Tex. The central portions 36, 38 and the rear, carriageportions 28, 30 may be part of a trailer. FIG. 2 a is a side view of atrailer 43 a, which may be part of the first vehicle 12 separated fromthe forward, truck portion 24. A similar trailer 43 b for the secondvehicle 16 is discussed in more detail with respect to FIG. 5. One ofthe rails 40 and the rear carriage portion 28 are shown, as well. Thesource 14 and other structures shown on the first vehicle 12 in FIG. 1are not shown in FIG. 2 a, for ease of illustration. The forward ends 41of the rails 40 are coupled to a pivot support structure 45, thatincludes a pivot 45 a (known as a kingpin) that may be releasablycoupled to the forward, truck portion 24, in a manner known in the art.Supporting legs 45 b, one of which is shown in FIG. 2 a, may extend fromthe pivot structure 45, to support the trailer 43 a when the trailer isnot coupled to the forward truck portion 24. The legs 45 b may beretracted within the pivot support structure 45 to adjust the height ofthe legs, as is also known in the art. The supporting legs may extendfrom the rails, instead. An example of an appropriate trailer 43 a isidentified below.

Returning to FIG. 1, the source 16 may be supported on a carriage 44with wheels 47 to facilitate movement along the rails 40. The wheels 47may be received within one or more channels 48 in the rails 40.Similarly, the detector 18 may be supported on a carriage 50 with wheels52 movable within channels 54 in the rails 42 of the second vehicle 16.FIG. 3 is a cross-sectional view of one of the rails 40 through line 3—3of FIG. 2 a, better showing the channel 48. The channels 52 in the rails42 are similar.

The carriages 44, 50 may be driven by electric, direct drive motors (notshown) coupled to the wheels 47, 52. The motors may be variable speed ACvector drive electric motors, for example. Appropriate motors arereadily commercially available. The drive speed may be about 100 feet(about 30.48 meters) per minute.

A tachometer coupled to the source 14 or motor moving the source may beused to synchronize movement of the detector 18 (or vice versa) so thatthey stay aligned during scanning. A proportional integral derivative(PID) loop derived from an absolute positional reference system may beused to correct for errors in the motion of the detector 18, forexample.

Alternatively, the carriages 44, 50 may be driven by motor drivenendless belts moving within the channels 48, 52. In another alternative,the carriages may be supported and moved by an air cushion generated bycompressed air.

Preferably, the rails 40, 42 are telescoping rails, comprising firstsections 40 a, 42 a, received within second sections 40 b, 42 b,respectively, as shown in FIGS. 1 and 2 a. More preferably, third railsections 40 c are received within the first sections 40 a, 42 a,respectively, as shown in FIG. 2 b, to provide for additional length. InFIGS. 1, 2 a and 2 b, the rails 40, 42 are in a first, deployedposition, wherein the first rails 40 a, 42 a extend from the secondrails 40 b, 42 b, to extend the lengths of the central portions 36, 38of the first and second vehicles 12, 16, at least beyond the length ofthe cargo conveyance 20 to be scanned. Preferably, the lengths of thecentral portions 36, 38 extend beyond the length of the third vehicle 22supporting the cargo conveyance 20, as well, as shown in FIG. 1, so thatthe entire vehicle 22 may be scanned.

FIG. 4 is a perspective view of the second vehicle 16, including theforward, truck portion 26 coupled to a trailer 43 b. The rails 42 are ina second, non-deployed position, wherein the first rail sections 40 aare received within the second rail sections 40 b along much of theirlengths, reducing the length of the vehicles. The vehicle 14 may therebybe more readily driven to and from an inspection site. The rails 40 offirst vehicle 16 preferably have a similar second, non-deployed positionto facilitate driving, as well. The reduced length of the vehicles 12,16 also avoids the need for special permits to drive the vehicles on theroads.

FIG. 5 is a side view of the trailer 43 b with the rails 40 in theirsecond, non-deployed position. In FIG. 5 (and FIG. 4) the detector 18 isshown in a preferred, non-deployed position in which the detector ishorizontal, to protect the detector 18 during driving. In FIG. 1, thedetector 18 extends vertically in a deployed position, to detect avertically diverging fan beam of radiation transmitted through the cargoconveyance 20 a. The detector 18 may be mounted to the carriage 50 via apivot 51, shown best in FIG. 5. A motor (not shown) coupled to the pivot51 and detector 18 may rotate the detector from the non-deployedposition to the deployed position before, during or after the rails areextended from the second, non-deployed position to the first, deployedposition.

The trailers 43 a, 43 b may have lengths L1 of about 70 feet (about 21.3meters), for example, when in the first, deployed position, as shown inFIG. 2 a. The extended rails themselves may have a length of about 52feet (about 15.8 meters), providing a scanning length of about thatlength. With an additional set of rails 43 c received with the rails 43b, as shown in FIG. 2 b, the trailers 43 a, 43 b may have lengths L2 ofabout 107 feet (about 32.6 meters), for example. The extended rails 40,42 in FIG. 2 b may have a length of about 87 feet (about 26.5 meters),providing a scanning length of about that length. When in the second,non-deployed position of FIG. 5, the trailers 43 a, 43 b may havelengths L3 of about 53 feet (about 16.2 meters), for example. A 53-foottrailer 43 a, 43 b may be driven by a truck 24, 26 without a permit. Therails 40, 42 may be extended from the non-deployed to the deployedposition by releasing a lock securing the rails together, and drivingthe truck portions 24, 26 of the vehicles 14, 16 forward a desireddistance. Telescoping trailers 43 are known in the art. Suitabletelescoping trailers are available from Talbert Manufacturing, Inc.,Rensselaer, Ind. (“Talbert”), under the tradename Double Drop Trailer,for example. The Talbert Double Drop Trailers have one pair of railsreceived within another pair of rails, as in FIG. 2 a. An additionalpair of telescoping rails, as in FIG. 2 b, may be readily provided inthe Talbert Double Drop Trailers. The Talbert Double Drop Trailers havean auto-leveling option, to compensate for irregular terrain.

As mentioned above, the supporting legs 45 b, shown in FIGS. 2 and 5,are preferably retractable. The rear wheels 32, 34 of the rear, carriageportions 28, 30 of the first and second vehicles 12, 14 are alsopreferably retractable. During use, the forward, truck portions 24, 26of the vehicles 12, 14 are preferably separated from the trailers 43, 43b, respectively, after the rails 40, 42 of the trailers 43 a, 43 b areextended to their deployed positions. The wheels 32, 34 and the legs 45b are retracted, lowering the rails 40, 42 to the ground, for supportduring operation, as shown in FIG. 6. The Talbot Double Drop Trailersmay be obtained with retractable legs and wheels, as well.

FIG. 7 is a front view of the source 14 and the detector 18 of theradiation scanning system 10 during use scanning the cargo conveyance 20on the third vehicle 22 (the wheels 22 a of the third vehicle areshown). The source 14 and the detector 18 are shown supported by thecarriages 44, 50 and the rails 40, 42, respectively. Preferably, theradiation beam is a vertically diverging beam B, as shown in FIG. 7.More preferably, the radiation beam is a vertically diverging fan beam.A cone beam may be used, as well. The detector 18 extends vertically asufficient distance to collect the radiation beam B after interactingwith the cargo conveyance 20. Here, the term “fan beam” refers to adiverging radiation beam having essentially only one dimension, such asa vertical dimension. The term “cone beam” refers to a two dimensionaldiverging radiation beam, such as a radiation beam that divergeshorizontally and vertically. The cone beam need not be a mathematicalcone; it may be an arbitrarily shaped cone with a cross-section havingan outer edge with a rectangular, square, circular or elliptical shape,for example.

The vertically diverging beam 43 may be defined by one or morecollimators 62, as is known in the art. The collimator 62 may beintegrated with the source 14. The vertical height of the verticallydiverging beam at the face 20 a of the cargo conveyance 20 may beslightly greater than the height of the conveyance. Since the source 14is close to the ground, in order to irradiate an entire vertical sliceof the cargo conveyance 20, the collimator 62 may be an asymmetricalcollimator. The arc α of the radiation beam B may be about 90 degrees,for example. It may extend from about −20 degrees to about +70 degrees,for example with respect to a vertical line V. The extent of the arc αand its orientation in a particular application depends on the distancebetween the source 14 and the detector 18, the height of the cargoconveyance 20 and the position of the cargo conveyance 20 in the gap.Alternatively, the direction of the central ray R of the source 12 maybe rotated upward, as shown in the schematic representation of FIG. 8.The central ray may be rotated by placing a wedge 64 between the source14 and the carriage 44, for example. At least part of the vehicle 22,including at least part of the wheels 22 a, may be scanned as well, bysuitably setting the dimensions of the components of the system 10 andthe distance between the first and second vehicles 12, 16.

The radiation source 14 may be a source of X-ray radiation, such asBremsstrahlung radiation, for example. The source 14 may emit radiationhaving an appropriate energy for the configuration of the system 10, thewidth “W” of the cargo conveyance 20 (see FIG. 9) and the contents ofthe cargo conveyance, which would be apparent to one of ordinary skillin the art. To examine a cargo conveyance 20 having a width W greaterthan about 5 feet (about 1.5 meters) by a radiation scanning system 10in accordance with the embodiment of FIG. 1, it would generally bedesirable for the X-ray source 14 to generate a radiation beam B havinga nominal energy greater than about 1 MV to penetrate through the entirewidth W of the conveyance, as is known in the art. If the contents ofthe conveyance 20 is not very dense, a lower energy may be used. Higherenergies may be used, as well. The source 14 may also emit radiation atmultiple energies.

The X-ray source 14 may be a linear accelerator, such as a Linatron®Linear Accelerator (“Linatron®”), available from Varian Medical Systems,Inc., Palo Alto, Calif. (“Varian”) for example, that emits radiation atone or more nominal energies. A Linatron® M9, with ultra-low leakage,which is capable of emitting radiation at nominal energies of 6 MeV and9 MeV, may be used, for example. A linear accelerator emitting radiationat other energies, such as 3.5 MeV and 6 MeV, or 5 MeV and 10 MeV, forexample, may also be used. Other types of X-ray sources may also beused, such as electrostatic accelerators, microtrons and betatrons, forexample. X-ray tubes may also be used, particularly for cargoconveyances and other objects having a width W less than about 5 feet(1.5 meters). Another possible radiation source is a radioactiveisotope, such as cobalt 60. Alternatively, neutrons or gamma rays may beused to scan the cargo conveyance 20. Neutron and gamma ray radiationsources are known in the art, as well.

The detector 18 may be a detector array. To detect a fan beam ofradiation, the detector array 18 may be a one dimensional detector arraycomprising one or more modules of detector elements, as is known in theart. Each one dimensional detector module may comprise a single row of aplurality of detector elements. Shielding may be provided in the back ofthe module and/or behind the detector array 18, as is known in the art.Preferably, the detector 18 and associated shielding extends beyond theprofile of the radiation beam, so that additional shielding is notnecessary. Additional shielding may be provided if desired, however.

The detector or detector array 18 may extend vertically when deployedand have a height “Hv”, as in FIG. 7, for example. The detector ordetector array 18 may also have a horizontal section 18 a perpendicularto vertical section 18 b, to extend over the cargo conveyance 20 whendeployed, as shown in phantom in FIG. 7. The vertical height of thedetector 18 could then be less than Hv. The horizontal section 18 a maybe connected to the vertical section 18 b by a pivot 18 c, for example,enabling the horizontal section to be folded against the verticalsection, when not deployed.

The detector elements may comprise a radiation sensitive detector, suchas a scintillator, and a photosensitive detector, such as a phototube orphotodiode, as is known in the art. A high density scintillator, such asa cadmium tungstate scintillator, may be used. The scintillator may havea density of 8 grams per cubic cm, for example. 2,000 detector elementswith a pitch of 2 mm may be provided in a linear array with a lineararray of photodiodes, for example. The vertical height Hv of thedetector 18 would then be 4,000 mm. Appropriate cadmium tungstatescintillators are available from Saint Gobain Crystals, Solon, Ohio,U.S.A. and Spectra-Physics Hilger Crystals, Kent, U.K. for example.Detector modules having detection efficiencies of from about 10% toabout 80% are preferably used, depending on the radiation spectrum ofthe radiation beam. If a cone beam of radiation is used, the detectorarray 18 may comprise one or more rows of two dimensional detectormodules. A two dimensional detectors module may comprise a plurality ofrows and columns of detector elements.

Returning to FIG. 1, supporting components for the source 14 may also bemounted on the first vehicle 12. For example, if the source 14 is alinear accelerator, a generator 64 to provide power to the source 14, anRF tub 65 containing a microwave generation system for the accelerator,a temperature control unit (“TCU”) 66 to stabilize the temperature ofthe linear accelerator, and a modulator 68 to modulate the pulsesdriving the linear accelerator, may be mounted on the first vehicle 12.Storage 70 may also be mounted on the first vehicle 12, to containaccessories used with the system 10, such as high voltage cables, quickconnect cables, water cooling hoses, spare parts and tools, for example.The generator 64 may be a 55 KVA generator, for example. The RF tub 65may be mounted on the source 14. Supporting components for the detector18, such as a generator 72 and signal processing system 74, may bemounted on the second vehicle 16. The generator 72 may be a 25 KVAgenerator, for example.

The detector array 18 is electrically coupled to the signal processingsystem 74, which may include a processor, such as a computer, andanalog-to-digital conversion circuitry (not shown). In one example, thesignal processing system 74 reconstructs the data output by the detectorarray 18 into images that may be displayed on a monitor 76. The monitor76 may be provided in a space 78 behind a driver's seat in one of thevehicles 12, 16, shown in phantom in FIG. 1. If the monitor 76 isprovided in one of the truck portions 24, 26, it is generally morepractical to provide the monitor 76 in the same vehicle that supportsthe detector (the second vehicle 16). The space 78 behind the seat mayhave a height of about 82 inches (about 2.08 meters) and a width ofabout 70 inches (about 1.78 meters), for example, which is more thanenough to accommodate the monitor 76 and an operator. The forward truckposition 26 may be suitably shielded to protect the operator, as isknown in the art.

The monitor 76 may also be located in a separate facility, such as amotor home or an office container. The separate facility may be at theinspection site or at a remote location. An office container could becarried on one of the first and second vehicles 12, 16 prior todeployment. The office container could be removed from the vehicle atthe inspection site, by a crane, for example. The remote location may beat a central office, for example. The display may be coupled to theimage processing circuit by wires or a radio frequency transmit/receivesystem, for example.

A control system 79 comprising one or more program logic controllers inone or more computers may be coupled to the monitor 76, to the motorscausing movement of the source 14 and the detector 18, to the signalprocessing system 74 and to other system components, via wires or awireless connection, to control their operation. The control system 79may be in the same location as the monitor 76, as shown in FIG. 1, or inanother location. Other control configurations may be used, as well.

The signal processing system 74 preferably enables real-time viewing ofan image of the contents of the cargo conveyance 20, as it is beingacquired. It also preferably enables an operator to pan (move a cursorto particular region of the image), zoom in on selected regions of theimage, conduct edge enhancement, reverse video (reverse state of darkand light regions), select pseudo coloring of the image based imagedensities, select contrast enhancement, and mark and annotate regions ofinterest. Two display monitors are preferably provided for side-by-sidecomparison of the same image under different test and displayconditions. For example, each monitor may display an image derived fromdata acquired at different energies. Data acquired at different energiesmay be merged for display on one monitor, as well. The image processormay be a PC based Pentium(R) 4 image processor, for example, with linescanning inspection software, as is known in the art. In this example,the signal processing system provides processed data to the controlsystem 79, which may further process the data for display on the monitor76.

Other system components may include a management database, disk storage(preferably for over 1,000 full scan images), a color laser printer anda document scanner. Preferably, the system has Internet access to sendimages to other locations for analysis. More preferably, the Internetaccess is wireless Internet access.

The detector array 18 may comprise detector elements or sensors todetect nuclear materials instead of or in addition to the detectorelements for imaging the contents of the cargo conveyance 20, describedabove. Detectors or sensors that detect radiation emitted by nuclearmaterial, are described in “Portable System from Berkeley NucleonicsDetects ‘Dirty Bombs’,” Berkeley Nucleonics, Jun. 12, 2002, available onYahoo! Finance, for example. Portal Monitors for the detection ofradioactive and special nuclear material, such as those available fromPolimaster Ltd, Minsk, Belarus, may also be adapted for use with thesystem of the present invention.

To use the system 10, an appropriate site is first identified. The siteneeds to be generally flat. The vehicles 12, 16 are then driven to theinspection site. The inspection site may be at or near a bordercrossing, a site of an emergency, a roadblock, along an approach to abridge, at a seaport or anywhere else inspection of objects such ascargo conveyances is needed. At the site, the first and second vehicles12, 16 drive in the direction of arrow C and park parallel to eachother, as shown in FIG. 1 and FIG. 9, which is a top schematic view ofthe first and second vehicles. Markings M1 may be provided along theground to indicate where the vehicles 12, 16 should stop. The front endsof the vehicles 12, 16 are preferably aligned within 3 inches (76.2 mm)of each other. The system 10 may compensate for small deviations in theterrain of the inspection site and misalignment of the first and secondvehicles 12, 16, by auto leveling of the system and/or by appropriateprocessing of acquired data. As mentioned above, the first and secondvehicles 12, 16 may be separated by a gap G of about 30 feet (about 9.14meters), for example. The alignment of the two vehicles 12, 16 may bechecked by a laser system, for example, as is known in the art.

After parking in a proper location, the rails 40, 42 are unlocked andthe forward truck portions 24, 26 of the first and second vehicles 16,18 are driven forward along arrow D to extend the rails 40, 42 a desireddistance, as shown in FIG. 10. Markings M2 may be provided along theground to indicate how far the truck portions 24, 26 should be driven.The alignment of the first and second vehicles 12, 16 may be verified bylaser again.

The forward, truck portions 24, 26 of the first and second vehicles 12,16 are then preferably separated from the vehicles. First, thesupporting legs 45 b of the trailers 43 a, 43 b are preferably extendedto support the trailers 43 a, 43 b on the ground. (See FIGS. 2 b and 5).The forward truck portions 24, 26 of the first and second vehicles 12,16 may then be disconnected from the trailers 43 a, 43 b, respectively,and driven away. The supporting legs 45 b and the wheels 32, 34 may nowbe retracted, to lower the rails 40, 42 to the ground, as shown in FIG.6. The detector 18 may be rotated into the vertical position before therails 42 are being extended, as they are being extended or afterwards.FIG. 11 shows the trailers 43 a, 43 b after the forward truck portions24, 26 are driven away. FIG. 11 also shows the detector 18 in itsdeployed, vertical position, as in FIGS. 1 and 7.

The cargo conveyance 20 to be inspected may then be driven between thetrailers 43 a, 43 b by the truck 22 along arrow E, as is also shown inFIG. 11. A marking M3 may be provided on the ground to indicate wherethe truck 22 should be positioned. Preferably, the cargo conveyance 20is closer to the second vehicle than to the first vehicle, decreasingthe size of the arc of the fan beam required to encompass the fullheight of the cargo conveyance 20, and decreasing the required height ofthe detector 18. The truck 22 may be driven into position from eitherdirection. The driver of the truck 22 would typically then leave thetruck 22, after which time inspection may commence.

In accordance with this embodiment, the radiation source 14 and thedetector 18 are synchronously moved along the rails 40, 42,respectively, from a first end 80 a to a second end 80 b of the rails,along arrows F, to conduct a line scan of the cargo conveyance 20 alongits entire length, as shown in FIG. 12. The cargo conveyance 20 may bescanned at two different energy levels, such as 6 MeV and 9 MeV, forexample. The source 14 may be rapidly switched between the two energylevels during scanning. Alternatively, the source 14 may emit radiationat one energy level when the source 14 and the detector 18 are movedfrom the first end 80 a to the second end 80 b and at the second energylevel when the source and the detector 18 are moved from the second end80 b to the first end 80 a of the rails 40, 42. The truck 20 may bescanned, as well, including at least part of the wheels 22 a (See FIG.7).

After scanning, the driver may return to the truck 22 and drive away. Asecond truck 22 a and cargo conveyance 20 a may then be driven betweenthe two trailers 12, 16 to be scanned. Both the source 14 and thedetector 18 will be at the second end 80 b of the rails 40, 42 afterscanning the first cargo conveyance 20. When scanning the second cargoconveyance 20 a, the source 14 and the detector 18 may be moved back tothe first end 80 a. Alternatively, the source 14 and the detector 18 maybe returned to the first end 80 a after scanning the first cargoconveyance 20, and prior to scanning the second conveyance.

To increase throughput of the scanning system 10, the system 10 maycomprise an additional vehicle similar to the second vehicle 16,supporting a second detector 84. FIG. 13 shows a trailer 82 of theadditional vehicle, parallel to the first trailer 43 a of the firstvehicle 12. A gap G2 is indicated between the trailer 82 and the trailer43 a. The second cargo conveyance 20 a may be driven into the gap G2 forinspection, by a second truck 22 a. The radiation source 14 on the firstvehicle 12 may be pivotally supported on the carriage 44 by a pivot 86,as shown in FIG. 14. After inspection of the first cargo conveyance 20,the source 14 may be rotated about an axis X to face the second cargoconveyance 86. The second cargo conveyance 20 a may then be inspected,preferably by moving the source 14 and the detector 18 from the secondend 80 b to the first end 80 a of the rails. While the second cargoconveyance 20 a is being inspected, a third cargo conveyance 20 b may bedriven into the gap G between the first and second vehicles by a thirdtruck 20 b. When inspection of the second cargo conveyance 20 a iscompleted, the source 14 may be rotated to face the third cargoconveyance 20 c. The third cargo conveyance 20 c may then be inspected,preferably by moving the source 14 and the detector 18 from the firstend 80 a to the second end 80 b of the rails 40, 42. This process may berepeated with subsequent cargo conveyances, nearly doubling thethroughput of the system 10.

Two cargo conveyances, 20, 20 a, one in each gap G, G2, may be inspectedsimultaneously by two sources 100 mounted on the same carriage 44,facing opposite directions, as shown in FIG. 15. First and second beamsB1, B2 are shown emitted in opposite directions. Alternatively, a secondsource 14 a, shown in phantom, may be mounted on a separate carriage,facing an opposite direction as the first source 14 of FIG. 12, forexample. If two sources 100 are used, operation of each source ispreferably controlled separately.

Alternatively, beams B1 and B2 may be emitted by a “panoramic” source100, adapted to emit radiation beams in opposite directions. A“panoramic” source is described in application Ser. No. 10/199,781,which was filed on Jul. 19, 2002, is assigned to the assignee of thepresent invention and is incorporated by reference, herein. FIG. 16 is atop, partial cross-sectional view of the panoramic source 110. Thepanoramic source 100 comprises a linear accelerator body 102, which maybe a Varian Linatron®, as described above, or may have otherconfigurations known in the art. The linear accelerator body 102 has anopen output end 103. An electron beam 104, shown in phantom, isaccelerated as it follows a path through the linear accelerator body 102along a longitudinal axis Y of the body. The electron beam 104 exits theaccelerator body from the output end 103. A proximal end of a tube 106,referred to as a drift tube, is connected to the output end 103 of thelinear accelerator body 102, in communication with and extending fromthe open output end. The drift tube 106 may have a diameter of fromabout 6 to about 10 mm, for example. The drift tube 106 may be the samematerial as the linear accelerator 102, to facilitate the connection ofthe drift tube to the linear accelerator body. The drift tube 106 andlinear accelerator body 102 may be metal for example. The drift tube andlinear accelerator body may be other materials, as well.

A target material 108 of a metal with a high atomic number and a highmelting point, such as tungsten or another refractory metal, is providedat the distal end of the drift tube 106. Shielding material 110, such astungsten, steel or lead, is provided around the drift tube 106, and thetarget material 108 and may extend over a distal portion of the linearaccelerator body 102, as well. The shielding material 110 may be in theshape of a sphere, for example, and the target material 108 may be atthe center of sphere, within the drift tube 106. The shielding material110 may also have other shapes. The drift tube 106, the target material108 and the shielding material are referred to as a “shielded target111”.

First and second collimating slots 112 a, 112 b extend from the end ofthe drift tube 106, through the shielding material 110, transverse tothe longitudinal axis L1 of the linear accelerator body 102. The slots112 a, 112 b are shaped to collimate the X-ray beam emitted by thetarget material into a vertically diverging beam, such as a fan beam ora cone beam, which is emitted from the shielded target in oppositedirections, perpendicular to the axis Y of the accelerator body 102. Theslots 112 a, 112 b have first angular dimensions θ1, that define thehorizontal width of the vertically diverging beam. The slots 112 a and112 b will typically have the same angular dimension θ1, but that is notrequired. θ1, which is shown exaggerated in this view, will typically besmall to define a small horizontal dimension of a vertically divergingfan beam. FIG. 17 is a cross-sectional view of the shielded target 111along axis 17 in FIG. 16, showing second angular dimensions θ2 of theslots 112 a, 112 b. The second angular dimension θ2 defines the angle ofthe fan beam, which may be about 90 degrees, for example.

The electron beam 104 emitted by the linear accelerator body 102 alongthe longitudinal axis L1 passes through the drift tube 106 and impactsthe material 108. Bremsstrahlung X-ray radiation is emitted from thetarget material 108 in all directions. The radiation emitted in thedirection of the collimating slots 112 a, 112 b is collimated into thedesired shape and emitted from the device 100. The shielding material110 absorbs radiation emitted in other directions.

FIG. 18 shows the radiation source 100 with a shielded target 111supported by the carriage 44. The wheels 47 of the carriage 44 and therails 40 of the first vehicle 12 are also shown, as are the cargoconveyance 20 and the cargo conveyance 20 a. Additional components ofthe system, such as the detectors 18, 84 and the trailers 43 a, 82, arenot shown to ease illustration. The source 100 is shown emitting twovertical fan beams B1, B2 simultaneously towards the cargo conveyance 20and the cargo conveyance 20 a, respectively.

The radiation scanning system 10 in accordance with embodiments of thepresent invention is mobile, may be easily transportable is inexpensiveand may be simply and rapidly, deployed. The vehicles 12, 16 of thesystem 10 may be driven without permits. The system may be operated byonly two people.

While in the preferred embodiments described above, one or more cargoconveyances supported by trucks are inspected, the system of the presentinvention may be used to inspect cargo conveyances supported by othertypes of vehicles or in other ways. Other types of objects can also beinspected. For example, motor vehicles, such as trucks and buses, couldbe inspected. While the trailers 43 a, 43 b described above aretelescoping, it is noted that telescoping is not required, particularlywhen inspecting shorter objects.

In addition, while the source 14 and the detector 18 are movable acrossthe lengths of the telescoping portions of the vehicles 12, 16 in theembodiments above, the source 14 and/or the detector 18 may be moved bya telescoping portion of a respective vehicle.

One of ordinary skill in the art will recognize that changes may be madeto the preferred embodiments described above without departing from thespirit and scope of the invention, which is defined by the claims,below.

1. A vehicle for use in a radiation scanning system, the vehiclecomprising: a trailer comprising a supporting portion extendinglongitudinally along a longitudinal axis of the vehicle, the supportingportion comprising an expandable portion; a truck releasably coupled tothe trailer; and a radiation source movable on the supporting portion.2. The vehicle of claim 1, wherein: the expandable portion has a firstposition supported above ground and a second, lowered position, on theground.
 3. The vehicle of claim 1, wherein: the expandable portioncomprises at least one rail to movably support the source.
 4. Thevehicle of claim 3, wherein: the at least one rail is telescoping. 5.The vehicle of claim 1, wherein: the expandable portion is telescoping.6. The vehicle of claim 1, wherein: the radiation source is a source ofX-ray radiation.
 7. The vehicle of claim 1, further comprising: a baseto support the source; wherein the source is rotatably coupled to thebase for selective rotation.
 8. The vehicle of claim 1, wherein: thesupporting portion extends longitudinally in a direction of alongitudinal axis of the vehicle.
 9. The vehicle of claim 1, furthercomprising: at least one wheel between the radiation source and thesupporting portion, wherein the radiation source is movable on thesupporting portion by rolling of the at least one wheel.
 10. A vehiclefor use in a radiation scanning system, the vehicle comprising: asupporting portion extending longitudinally along a longitudinal axis ofthe vehicle; and a radiation source movable on the supporting portion;wherein the source is adapted to emit at least two radiation beams inopposite directions, simultaneously.
 11. A vehicle for use in aradiation scanning system, the vehicle comprising: a supporting portionextending longitudinally along a longitudinal axis of the vehicle; afirst radiation source movable on the supporting portion; and a secondradiation source movable on the supporting portion.
 12. A vehicle foruse in a radiation scanning system, the vehicle comprising: a trailercomprising a supporting portion extending longitudinally along alongitudinal axis of the vehicle, the supporting portion comprising anexpandable portion; a truck releasably coupled to the trailer; and adetector to detect radiation, the detector being movable on thesupporting portion.
 13. The vehicle of claim 12, wherein: the expandableportion has a first position supported above ground and a second,lowered position, on the ground.
 14. The vehicle of claim 12, wherein:the supporting portion comprises at least one rail to movably supportthe detector.
 15. The vehicle of claim 14, wherein: the at least onerail is telescoping.
 16. The vehicle of claim 12, wherein: theexpandable portion is telescoping.
 17. The vehicle of claim 12, wherein:the detector has a deployed position to detect radiation; and thedetector has a non-deployed position.
 18. The vehicle of claim 17,wherein: the non-deployed position is a horizontal position, along thesupporting portion.
 19. The vehicle of claim 12, wherein: the detectoris adapted to detect X-ray radiation.
 20. The vehicle of claim 12,wherein: the detector is adapted to detect a vertically divergingradiation beam.
 21. The vehicle of claim 12, further comprising: atleast one wheel between the detector and the supporting portion, whereinthe detector is movable on the supporting portion by rolling the atleast one wheel.
 22. A vehicle for use in a radiation scanning system,the vehicle comprising: a trailer comprising a supporting portion, thesupporting portion comprising an expandable portion; a truck releasablycoupled to the trailer; a base movable on the supporting portion; and aradiation source rotatably coupled to the base, wherein the source isselectively rotatable with respect to the base, to selectivelyilluminate objects in different locations.
 23. The vehicle of claim 22,wherein; the radiation source is pivotally coupled to the base.
 24. Thevehicle of claim 23, wherein: the supporting portion comprises anexpandable portion.
 25. A vehicle for use in a radiation scanningsystem, the vehicle comprising: a forward portion; a rearward portion; asupporting portion coupling the forward portion to the rearward portion,the supporting portion being telescopically expandable to vary a lengthof the vehicle; and a radiation source movable on the supportingportion, between the forward portion and the rearward portion.
 26. Thevehicle of claim 25, wherein: the supporting portion is expandable alonga longitudinal axis of the vehicle; and the radiation source is movable,on the supporting portion, along the longitudinal axis of the vehicle.27. The vehicle of claim 25, further comprising: at least one wheelsupporting the forward portion and at least one wheel supporting therearward portion.
 28. The vehicle of claim 25, further comprising: atleast one wheel between the radiation source and the supporting portion,wherein the radiation source is movable on the supporting portion byrolling the at least one wheel.
 29. The wheel of claim 28, wherein theradiation source is coupled to the wheel, to enable the radiation sourceto roll along the supporting portion.
 30. The wheel of claim 28, whereinthe detector is coupled to the wheel, to enable the detector to rollalong the supporting portion.
 31. A vehicle for use in a radiationscanning system, the vehicle comprising: a forward portion; a rearwardportion; a supporting portion coupling the forward portion to therearward portion, the supporting portion being telescopically expandableto vary a length of the vehicle; and a detector movable on thesupporting portion, between the forward portion and the rearwardportion.
 32. The vehicle of claim 31, wherein: the supporting portion isexpandable along a longitudinal axis of the vehicle; and the radiationsource is movable, on the supporting portion, along the longitudinalaxis of the vehicle.
 33. The vehicle of claim 31, further comprising: atleast one wheel supporting the forward portion and at least one wheelsupporting the rearward portion.
 34. The vehicle of claim 31, furthercomprising: at least one wheel between the detector and the supportingportion, wherein the detector is movable on the supporting portion byrolling the at least one wheel.
 35. A vehicle for use in a radiationscanning system, the vehicle comprising: a trailer comprising asupporting portion; a radiation source movable on the supportingportion; and at least one wheel between the radiation source and thesupporting portion, wherein the radiation source is movable on thesupporting portion by rolling of the at least one wheel.
 36. The vehicleof claim 35, further comprising: a truck coupled to the trailer.
 37. Thevehicle of claim 36, wherein: the truck is releasably coupled to thetrailer.
 38. The vehicle of claim 35, wherein: the supporting portionfurther comprises an expandable portion.
 39. The vehicle of claim 35,wherein: the radiation source is a source of X-ray radiation.
 40. Thevehicle of claim 35, wherein: the radiation source is adapted to emit atleast two radiation beams in opposite directions, simultaneously.
 41. Avehicle for use in a radiation scanning system, the vehicle comprising:a trailer comprising a supporting portion; a detector movable on thesupporting portion; and at least one wheel between the detector and thesupporting portion, wherein the detector is movable on the supportingportion by rolling of the at least one wheel.
 42. The vehicle of claim41, further comprising: a truck coupled to the trailer.
 43. The vehicleof claim 42, wherein: the truck is releasably coupled to the trailer.44. The vehicle of claim 41, wherein: the supporting portion furthercomprises an expandable portion.
 45. The vehicle of claim 41, wherein:the detector has a deployed position to detect radiation; and thedetector has a non-deployed position.
 46. The vehicle of claim 45,wherein: the non-deployed position is a horizontal position, along thesupporting portion.
 47. The vehicle of claim 41, wherein: the detectoris adapted to detect X-ray radiation.
 48. The vehicle of claim 41,wherein: the detector is adapted to detect a vertically divergingradiation beam.